Updated code comments on CalcCteFrac in pcte_funcs.c.
Updated code comments on CalcCteFrac in pcte_funcs.c.

git-svn-id: cc674101e2b794ddc2100b657215d55256e3fd48@13354 fe389314-cf27-0410-b35b-8c050e845b92

jhunkeler/hstcal,jhunkeler/hstcal,jhunkeler/hstcal